The present invention relates to a skin material, a skinned cushion, and a process for producing the skinned cushion.
Among the cushions for use in automotive seats and the like are skinned cushions such as that shown in FIG. 12. This skinned cushion 60 comprises a cushion main body 55 formed by foam molding in a mold so as to have a given shape and a skin material 50 bonded to a surface of the cushion main body 55 in a later step. Frequently used as this skin material 50 are sheet materials having a three-layer structure formed by bonding a flexible polyurethane foam to the back side of a fabric, plastic sheet, or the like and bonding a tricot, nonwoven fabric, or the like as a backing fabric to the back side of the flexible polyurethane foam for the purposes of imparting to the skin material improved slip properties required for sewing and of improving the strength and other properties of the skin material which are required during use.
However, the conventional skinned cushion 60 has the following drawback. The skin material 50 covering a surface of the cushion main body 55 is bonded thereto throughout the whole surface. Because of this, even when the skin material 50 used is air-permeable, the spaces among the weaving or knitting yarns in the skin material 50 or the breathing holes in the skin material 50 are clogged with the adhesive 57 and this impairs the air permeability of the surface of the cushion 60. As a result, the person sitting on the cushion 60 feels uncomfortable because the buttocks in contact with the surface of the cushion 60 become moist. This cushion 60 further has a drawback that since the surface pores of the cushion main body 55 are clogged by the complete bonding of the skin material 50 to the cushion main body 55, cushioning properties are impaired.
Furthermore, production of the skinned cushion 60 has the following drawback. In the production thereof, a solvent-based adhesive 57 is applied by spraying on a surface of a cushion main body 55, and a skin material 50 is superposed on the coated surface of the cushion main body 55 in preparation for press molding. However, once the skin material 50 comes into contact with the coated surface of the cushion main body 55, it is difficult to shift the skin material 50 thereon because the surface coated with the solvent-based adhesive 57 has become tacky. Namely, precise positioning of the skin material 50 on the cushion main body 55 is extremely difficult. There is hence a problem that not only great care should be taken in bonding the skin material 50, making this operation difficult, but also bonding failures are apt to result. In addition, there is an environmental problem that solvent volatilization occurs during the adhesive application by spraying to impair the working atmosphere.
Moreover, there has been a problem that when the three-layer skin material is put on the cushion main body or when the cushion main body covered with the skin material is set in a mold for pressing, the skin material surface is apt to crease in curved areas such as corners to impair the appearance of the skinned cushion obtained.
Further, JP-A-6-182067 proposes a cushion material comprising a cushion pad part and a skin layer which is bonded and formed on the surface thereof through an adhesive layer, wherein the skin layer comprises an air-permeable surface layer for decoration, a flexible polyurethane foam sheet layer which arranged on the lower side of the air-permeable surface layer by bonding and a thermoplastic resin film layer which is arranged on the lower side of the flexible polyurethane foam sheet layer by bonding, numerous recesses are arranged at least on the contacting surface of the flexible polyurethane foam sheet layer with the thermoplastic resin film layer, and the surface other than the numerous recesses is covered with the thermoplastic resin film layer with the top of the recesses being opened, and wherein a moisture hardening type reactive hot melt adhesive is used to bond a skin material on the pad, and steam is supplied to the reactive adhesive through the air-permeable skin material to harden by activating the adhesive, by which the cushion material is provided which is somewhat improved in seating confortableness and is hard to allow the impairing of texture of the surface to some extent with resistance to possible wrinkling on a surface layer even when it is bent being placed inside. (The term xe2x80x9cJP-Axe2x80x9d as used herein means an xe2x80x9cunexamined published Japanese patent applicationxe2x80x9d)
JP-A-7-195600 proposes a sheet material which is characterized in that a vinyl resin is adhered on at least one side surface of a foamed polyurethane sheet in such a manner as to form scattering dots of the vinyl resin, by which the manufactured sheet material is provided which is improved in sliding properties required at the time of manufacturing a skin material such as a sheet for a vehicle to some extent, and accordingly can be stitched and sewed on a sewing machine and does not generate few crease.
The invention has been achieved in view of the problems described above. An object of the invention is to provide a skin material which gives a skinned cushion having excellent air permeability and excellent cushioning properties in the seating area and can be precisely and easily bonded to a cushion main body while preventing the working atmosphere from becoming worse due to solvent volatilization, and which is less apt to crease in curved areas. Another object of the invention is to provide a skinned cushion. Still another object of the invention is to provide a process for producing the skinned cushion.
The invention provides a skin material which comprises an air-permeable sheet and an adhesive layer formed on the back side of the sheet by applying a melt of a hot-melt adhesive in such a manner as to form scattering dots of the melt or to leave scattering uncoated dot areas and hardening the melt.
The invention further provides a skinned cushion produced by bonding a skin material comprising an air-permeable sheet constituting the front side surface of the skin material to a surface of a cushion main body through an adhesive layer formed on the back side of the skin material, wherein the adhesive layer is constituted of a hot-melt adhesive interposed between the air-permeable sheet and the cushion main body so as to form scattering dots of the adhesive or to leave scattering uncoated dot areas.
The invention furthermore provides a process for producing a skinned cushion comprising a cushion main body and a skin material bonded to a surface thereof, which comprises: applying a melt of a hot-melt adhesive on the back side of an air-permeable sheet in such a manner as to form scattering dots of the melt or to leave scattering uncoated dot areas and hardening the melt to form a skin material comprising the air-permeable sheet having an adhesive layer on the back side thereof; and superposing the skin material on a surface of a cushion main body so that the adhesive layer faces inside and hot-pressing the skin material against the cushion main body to activate the hot-melt adhesive of the adhesive layer and thereby bond the skin material to the surface of the cushion main body while leaving unbonded areas between the skin material and the cushion main body.